Drop support for PHP 7.2

Manually merge 2.11.x into 3.0.x

Drop Doctrine\DBAL\Version in favor of Ocramius\PackageVersions

CompositeExpression and()/or() factory methods

Deprecated the usage of the Version class

Specify the platform configuration in composer.json

Deprecate calling QueryBuilder methods with an array argument

Prepare CompositeExpression for immutability

First parameter of ExpressionBuilder::and/or() mandatory

Rename andX() / orX() methods

Added builds against PHP nightly on Travis

According to the [documentation](https://docs.travis-ci.com/user/reference/trusty/#container-based-infrastructure), `sudo: false` is no longed needed since Trusty.

Backport PDO-related changes from master to 3.0.x

Use a wrapped PDO Statement instead of a custom class for `pdo_sqlsrv` since `PDOSqlsrv\Statement` doesn't extend `PDOStatement` anymore.